Improvement in machines for grinding wood for paper-pulp



l 5r. annui-1n.` Machine for Grinding Woo-d for Paper-Pulp.

Patented. March 23, 1875K.

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iwr rrrc BENJAMIN Fl. BARKER, OF CURTISVILLE, MASSACHUSETTS.

IMPROVEMENT IN MACHINES FOR GRINDING WOOD FOR PAPER-PULP.

Specification formingpart of-Letters Patent No. 160,996, dated March 23,11575; application filed August 6, 1874.

To all whom it may eoncernf Be it known that I, BENJAMIN F. BARKER, ofGurtisville, Berkshire county, Massachusetts, have invented certainImprovements relating to Machines for Grinding Wood for Pulp, of whichthe following is a specification:

The invention relates to the means of applying and feeding the wood tothe grinding-stone.

'Ihe mill is of that class where a burr-stone or other suitable stone isrevolved on a vertical axis, and acts on the wood at its periphery. TheWood is applied in short lengths, held with the grain parallel to theaxis of the stone. It is drawn by the motion of the stone into agradually-contractingor wedgelike space. It is wedged forward into thisspace, and consequently into intimate contact with the stone, partly bythe motion of the stone itself, and partly by a force applied throughthe medium of a pushing-piece thrust in from behind. When the wood ispartially consumed the pusher is drawn back, and fresh pieces of woodare applied, which are then acted on by the pusher.

Corresponding pushing-pieces have been before used, acting by the forceof springs. It

is difficult in practice to make the action of springs uniformlyreliable.

I form teeth on the under side of the pusherbar, match therein the teethof a small pinion, extend the shaft of the pinion outside of themill-casing, and x thereon a large grooved pulley and crank. The hand ofan attendant applied to the crank draws back the pusher by a simple andeasy movement. A weighted cord wound in the groove on the pulley gives auniform force to the pusher in pressing forward the wood. I provide anautomatic stop for the motion of the pusher by mounting a hinged pieceor pawl close to one face of the pulley, and fixing a pin in thepulley-face, which stops against the hook of the pawl when the pusherhas been driven to its extreme forward position. i

In winding up the weight and running back the pusher, thepawl isautomatically lifted to allow the passage of the pin7 and then falling,engages the pin and holds the pusher in the extreme backward position,to allow fresh wood to be inserted at leisure. When the at- Jtendant hasgot the wood properly in place he devices complete with the adjacentportion of the stone. I propose to use four of these feeders with astone ofthe ordinary size.

Figure 1 s a plan view, and Fig. 2 a side elevation.

Similarletters of reference indicate like parts in all the gures.

G is'the stone; M, the pusher-plate; b, a

curved pusher rod or rack of rectangular cross- Y section; E, thestationary casing around the stone, and G adj Listing-screws tappedthrough the casing E, and acting against an adjustable curved piece, H,which is hinged to the casing E at the point h, and is adjustable at theother end by the screws G, so as to stand close to, but withouttouching, the periphery of the stone C. rEhe bottom of the casing Hisinclined relatively to the motion of the stone, so that the wood, inbeing fed forward therein, moves downward as well as forward, thustending to avoid the formation of grooves on the stone or wood. J is apinion fixed on the shaft c', and meshing into the teeth on the underAside of the pusher-rod b. K is a grooved pulley fixed on the shaft 'ioutside of the cas'- ing E, and k is the handle or crank-pin set in thepulleyK, and extending snfcientlythrou gh the same to form a stop on theinner face, which is engaged by the pawl L turning on the pivot a l. Nis aweight attached to the cord n,which is wound in the groove in theperiphery of the pulley K. The size of the pinion J should be such thatone complete revolution thereof induces the full proper range ortraverse of the pusher-rod b. The latter is guided in a slot where itenters the casing H, and also in an eye, E', fixed on the inner face ofthe casing E. The acting end of the pawl L is beveled so that it islifted automatically when the cranked pulley K is turned around to drawback the pusher. It falls as soon as the pin k has passed it, and, whenthus conditioned, it supports the weight N, holding the pusher back outof the way for an indefinite period.

The means heretofore proposed for feeding forward the wood have beenobjectionable in several important points, which this apparatusovercomes. Springs of any ordinary construction are unreliable, andexert a sensibly greater pressure when forced back to their fullestextent, growing less as the pusher moves forward. Serious labor wasimposed upon the attendant in forcing` back the spring, and he wasobliged to hold it during the hasty andconsequentlyimperfectadjustmentot'thewood.

With my improved feeder the wood can be selected and tted with anydesired degree of nicety. VVllen all is ready, the touch of a nger tolift the pawl L allows the p ushing-force to be `instantly applied. Itis thereafter uniformly maintained until the pusher is moved to itsextreme forward position, when it is positively and firmly stopped.

A delicate female or other attendant with little strength can maintainthe proper action in a considerable number of these feeders withoutsevere labor.

I am aware that wood has been fed to a stone by a direct radialmovement, actuated by a weight, and with means for pulling back andholding back the forcing-plate; but I know of no previous attempt toapply any corresponding device to the circular feeding, which isessential to the proper presentation of large quantities of wood withgentle feeding-force.

My oblique casings H allow a slight force to urge the wood veryeciently, being aided by the drawing action due to the motion of thestone.

I claim as my invention- 1. In combination with the stone C and obliquecasing E, the feeder M, curved rack b, pinion J, pulley K, and weightedcord n, operating together as herein specified.

2. In combination with the stone C, casing H, feeder M, connected pulleyK, and pin k, the stop-pawl L serving to arrest the feeder at both endsof its motion, as herein specified.

In testimony whereof I have hereunto set my hand this 23d day of July,1874, in the presence of two subscribing witnesses.

BENJAMIN F. BARKER.

Witnesses:

H. M. BUNALL, W. R. CLARKE.

